Found da leak!!!!!!!!!!! It is at the pump/block mating surface. Apparently I didn't seal it good enough. Spent an hour looking for it with a mirror. The breeze from the fan would push the leak around to the hose connection. The leak is very small, about a drip per minute, hard to see but does make an obvious mess. Really don't want to pull the pump 'cuz its a real bear to get out, and worse to get back in while trying not to disturb a sealant bead. Has anyone had experience or recommend radiator stop leak additives. The coolant system is nonpressurized, and the block and rad was thoroughly cleaned by pros during rebuild so it shouldn't be too challenging for an additive. Thanks again for comments
